1. For the marinade: In a small saucepan, combine water, vinegar, sugar, and salt and bring to a boil. Immediately remove from heat and let cool to room temperature. Cut the lotus root into 1/8 in. (3mm) thick rounds and soak in vinegared water for 5 minutes. Briefly blanch in boiling water and soak in the marinade until flavored, for 20 minutes.

2. Slice the red onion into very thin slices. If the onion is bitter, soak in ice-cold water for about 20 minutes to crisp it and remove harshness. Drain well.

3. Have ice water ready in a small bowl. In a small saucepan, bring salted water to a boil and blanch the snow peas for about 2 minutes. Using a spider strainer, transfer the snow peas into the ice water to stop cooking. Drain.

4. Cut the tomato into 6-8 wedges. Lightly pound the cucumber on a cutting board with a rolling pin to soften it and allow the dressing to penetrate, and cut into 1-1/4 in. (3.5cm) lengths.

5. For the dressing: in a medium bowl, beat egg yolk and gradually add 5 Tbsp. of the vegetable oil, first drop by drop, then in a very thin stream whisking vigorously all the while. The oil should be completely emulsified. If it is broken, start over with a new egg yolk. Mix in miso, sudachi citrus juice and soy sauce, and adjust thickness by whisking in about 3 tbsp. of the vegetable oil.

6. Pat dry onion and snow peas. Arrange all vegetables on a serving plate. Spoon over the dressing and sprinkle with the sesame seeds.